LHRH regulates pituitary and non-pituitary systems. An understanding of the projections of the LHRH systems and the specific systems with which they interact aids in the understanding of the actions of the peptide. From initial studies of the interactions of the LHRH system, the tuberoinfundibular dopamine system and the magnocellular oxytocin or vasopressin network appear to be two systems that receive input from LHRH. In this proposal immunohistochemical techniques will be used to further characterize the anatomical relationship of LHRH containing processes with these systems and also define other possible systems on which LHRH may exert an influence. The role of LHRH in alerting the activity or function of the targeted system will then be determined by utilizing functional explants and measuring effects of LHRH on the release of vasopressin, or oxytocin by radioimmunoassay; a co-culture system which includes the tuberoinfundibular dopamine system and the anterior pituitary will be used to test LHRH effects on dopamine-mediated prolactin release. Since gonadal steroids influence the magnocellular systems and the tuberoinfundibular dopamine system, assessment of the influence of estrogen and/or testosterone on patterns of LHRH terminals and effects of LHRH on function of these systems will be examined in vitro with tissue from normal adult animals and in subjects with altered reproductive states such as gonadectomy, pregnancy and lactation. This knowledge is of importance for elucidation of the processes that regulate the reproductive system or are synchronized with the reproductive cycle.